1. Field
The present disclosure relates to a display device, and more particularly, to a cover window having an excellent optical property and a display device including the same.
2. Discussion of Related Art
As display technology has been developed, a display device, such as a liquid crystal display (LCD) device and an organic light emitting display (OLED) device, is used for a computer monitor, a television, a mobile phone and a smart apparatus.
The display device may include a display panel and a cover glass. The cover glass may be formed of tempered glass or plastic such that the display panel is protected by the cover window.
Generally, the cover glass and the display panel are attached by a direct bonding method. In the direct bonding method, the cover glass and the display panel are attached using an optical clear resin (OCR) or an optical clear adhesive (OCA).
FIG. 1 is a schematic cross-sectional view of the related art display device.
As shown in FIG. 1, the display device 1 includes a display panel 10, a cover glass 30 over the display panel 10 and an adhesive layer 20 between the display panel 10 and the cover glass 30. The adhesive layer 20 may be an OCA or an OCR.
Recently, a display device being capable of a touch operation is required. In addition, a foldable display device being flexible and/or bendable is required. As a result, a cover window being formed of plastic is used instead of the cover glass 30.
FIG. 2 is a schematic view illustrating a cover window for a foldable display device.
As shown in FIG. 2, a cover window 40 includes a soft region 34 and hard regions 32a and 32b adjacent to the soft region 34. The soft region 34 is formed of a soft material such as a urethane polymer, and the hard regions 32a and 32b are formed of a hard material such as polymethylmethacrylate (PMMA) or polycarbonate (PC). Since the material of the soft region 34 and the material of the hard regions 32a and 32b have a difference in a modulus property, the cover window 40 can be folded with respect to the soft region 34.
The foldable cover window 40 may be fabricated by a double injection molding method as one of a multi-component injection molding method. The soft material is filled in a mold and injected with holding pressure. Next, the hard material is filled in the mold to be adjacent to the soft material and injected with holding pressure. As a result, the foldable cover window 40 including the soft region 34 and the hard regions 32a and 32b can be provided.
High optical property is required in the cover window 40 for the display device. However, when the cover window 40 is used for the foldable display device, interfaces 36a and 36b between the soft region 34 and each of the hard regions 32a and 32b are observed.